Active Perturbation Rejection in Motion Control of Milling Machine Tools

Abstract

This article deals with the robust control problem of the motion axes of milling machine tools subjected to perturbation forces induced by the metal machining process. A position output feedback control scheme is proposed for robust rejection of unknown cutting and friction perturbation forces and robust tracking tasks of motion trajectories planned for a three-axis milling machine tool. The Coulomb friction, viscous damping and cutting forces are considered as terms of an unknown time-varying disturbance input signal affecting the dynamics of the motion axes of the milling machine. In the motion control design, the perturbation signal is modeled locally by a fourth degree Taylor time-polynomial family. Then, a state observer is designed to estimate the disturbance and velocity signals required for implementation of the proposed motion controllers. Simulation results are included to show the robust performance of the proposed motion control scheme and the fast and effective estimation of the perturbation and velocity signals.